In a wireless communications system, when receiving downlink service data sent by a core network device to user equipment, an access network device allocates an air interface resource for the user equipment, so that the access network device is capable of sending the downlink service data to the user equipment by using the air interface resource. For example, in an LTE (Long Term Evolution) system, the access network device may be a base station, the user equipment may be a mobile phone, and the air interface resource is a high frequency resource for transmitting information between the mobile phone and the base station. A frequency resource that can be used for transmitting information is limited, and therefore saving should be made as much as possible when the access network device allocates the air interface resource to the user equipment.
In the prior art, in order to ensure that a communication channel between user equipment and a core network device is normal and reachable, a hello keep-alive packet is sent between the user equipment and the core network device through an access network device. If a hello packet sent by the user equipment or the core network device is detected within a detection period, the access network device keeps an allocated air interface resource to the user equipment. If the hello packet sent by the user equipment or the core network device is not detected within the detection period, the access network device releases the air interface resource that is allocated to the user equipment, so that another user equipment uses the air interface resource.
However, in a practical application scenario, after acquiring an air interface resource, user equipment may not transmit service data by using the air interface resource for a long time, for example, a user stays a long time at a web page that has been loaded by user equipment. Because the user equipment does not perform any new service activity, the air interface resource is not used for transmitting service data within the period, which causes air interface resource waste.